This invention relates to an apparatus for applying force in one direction to an article and restraining movement of the article in the opposite direction. More specifically the apparatus is useful in the manufacture of refrigerators and particularly in the insulation foaming operation of refrigerator cabinets.
It has been recognized that certain foam resins permanently containing in their cells vapors having a low co-efficient of heat transmission provide superior insulating qualities to refrigerator and freezer cabinets. Refrigerator and freezers normally employ a sheet metal outer casing and either a sheet metal or plastic inner liner with an insulation medium interposed therebetween. Polyurethane compositions in liquid/gas form are introduced into the space between the outer casing and inner liner, expand throughout the space and then are solidified by curing. The pressures generated during the foaming operation require strong, heavy, expensive molds and fixtures to keep the refrigerator or freezer cabinet in its desired shape. These fixtures include a main frame with side gates that are movable in and out to prevent the side walls of the outer casing of the cabinet from being bulged or bowed outwardly during the foaming operation. The outer metal cabinet casing is usually prepainted and therefore it is important that the side gates which are to prevent bowing of the outer casing must be moved in a direction perpendicular to the surface of the article that it is to restrain so that the painted finish is not subject to abrasion, scratching, etc., by the side gates.
In the manufacture of refrigerator and freezer cabinets the outer metal casing is often subject to variation in tolerance which can be substantial enough that even though the side gates perform their proper operation, they do not allow for the variance in tolerance and therefore on many occasions during the foaming operation the outer casing of the cabinet is still permitted to bow outwardly until it is restrained by the side gate. One solution to the foaming process causing the outer casing to bow is to increase the amount of curing time that the refrigerator or freezer cabinet is subjected to in the fixture during the foaming process. This, however, is very expensive as it requires additional fixtures to be able to produce the same number of refrigerator cabinets foamed with shorter curing times. It is advantageous from the standpoint of minimizing the number of fixtures necessary for an assembly line and to minimize the amount of curing time per refrigerator cabinet that there be a means that allows shorter curing time yet prevents bowing of the refrigerator outer case due to manufacturing tolerance deviations of the outer casing.
By this invention there is provided apparatus that will accomplish the above-mentioned desirable results.